Life's utilization of B vitamins on early Earth.

Coenzymes are essential across all domains of life. B vitamins (B1 -thiamin, B2 -riboflavin, B3 -niacin, B5 -pantothenate, B6 -pyridoxine, B7 -biotin, and B12 -cobalamin) represent the largest class of coenzymes, which participate in a diverse set of reactions including C1 -rearrangements, DNA repair, electron transfer, and fatty acid synthesis. B vitamin structures range from simple to complex heterocycles, yet, despite this complexity, multiple lines of evidence exist for their ancient origins including abiotic synthesis under putative early Earth conditions and/or meteorite transport. Thus, some of these critical coenzymes likely preceded life on Earth. Some modern organisms can synthesize their own B vitamins de novo while others must either scavenge them from the environment or establish a symbiotic relationship with a B vitamin producer. B vitamin requirements are widespread in some of the most ancient metabolisms including all six carbon fixation pathways, sulfate reduction, sulfur disproportionation, methanogenesis, acetogenesis, and photosynthesis. Understanding modern metabolic B vitamin requirements is critical for understanding the evolutionary conditions of ancient metabolisms as well as the biogeochemical cycling of critical elements such as S, C, and O.

[Cerebellar syndrome caused by amiodarone]. / Síndrome cerebeloso por amiodarona.

Amidarone (AMD) is an antiarrhythmic drug with side effects on the nervous system. Cerebellum is seldom involved: We describe the case of a 56 years old male patient with a history of 4 month of cerebellar involvement characterized by gait unsteadiness, ataxia, nistagmus and vertigo. He was on treatment with AMD because of ventricular arrythmia. The cerebellar syndrome progressively disappeared after drug withdrawal and he was symptoms-free 4 months later. Similar symptoms appeared after another one month of automedication with the same drug. Structural lesions, metabolic, nutritional deficiencies or toxics were excluded. Mechanisms of cerebellar toxicity of AMD are yet unknown. The knowledge of the toxic effects of this drug, widely used in our country, would allow its early recognition.

Neurocisticercosis en un hospital de la ciudad de Buenos Aires: estudio de once casos / Neurocysticercosis in a hospital of the city of Buenos Aires: study of 11 cases

Fueron examiandos 11 pacientes adultos con el diagnostico presuntivo de neurocisticercosis, 8 de ellos provenientes de Bolivia y los restantes del interior de la Argentina. Como manifestación clínica inicial el 82 por ciento de ellos mostro convulsiones t el 73 por ciento cefaleas. Ambas alteraciones podian estar combinadas en el mismo paciente o presentarse en forma independiente. La tomografia computada de cerebro evidencio calcificaciones y quistes en 5 enfermos, solo calcificaciones en 3, hidrocefalia en 2 y un unico quiste en 1. En 7 casos se efectuo ELISA en el LCR, de ellos 6 resultaron positivos. El tratamiento medico se hizo en base a la administración de praziquantel o albendazolcon buena evolución de los pacientes en todos los casos. El tratamiento quirurgico fue indicado en el caso en que una lesión actuase como masa ocupante con aumento de la presión endocraneana (1 caso) o produjera obstrucción de la circulación del LCR llevando a una hidrocefalia (2 casos). El estudio presente pretende alertar sobre la posibilidad que nuevas regiones, como la Ciudad de Buenos Aires, puedan ingresar dentor del area endemica latinoamericana a consecuencia de los movimientos migratorios internos y externos y el asentamiento de portadores de la parasitosis en el perimetro urbano

[Neurocysticercosis in a hospital of the city of Buenos Aires: study of 11 cases]. / Neurocisticercosis en un hospital de la ciudad de Buenos Aires: estudio de once casos.

Eleven patients with diagnosis of possible neurocistycercosis were studied in our Department since 1986. All of them were adults. Eight were Bolivian citizens. The commonest neurological clinical manifestation were seizures and/or headache. Brain CT scans showed cystic lesions and calcifications in 5 patients, only calcifications in 3, enlarged ventricles in 2 and an isolated frontal cystic lesion in 1. Six out of 7 patients who were submitted to spinal fluid ELISA test showed positive response for cysticercosis. Patients were put on praziquantel (50 mg/Kg/d) or albendazol (15 mg/Kg/d) with good outcome for all them. Surgery was carried on for treatment of enlarged ventricles (2 patients) and for a like-expansive lesion (1 patient). The aim of this work is to underscore the fact that in Buenos Aires city, which previously was not within the endemic latin american area for cysticercosis, is now possible to find patients with the neurological manifestations of this parasitosis, most probably due to migration of people coming from the north provinces or from countries situated at its border where the disease is endemic.

Hidrocefalia crónica obstructiva por histoplasmosis meningo-cerebral / Chronic obstructive hydrocephalus due to meningeal and cerebral histoplasmosis

El presente caso describe un caso de histoplasmosis del sistema nervioso central con hidrocefalia obstructiva, que ha estado presente durante 8 años sin mayores secuelas o evidencias clínicas de infección activa en otros órganos, en un huésped inmunocompatible. La punción lumbar y el análisis del líquido cefalorraquídeo (LCR) revelaron un elevado nivel de proteínas, linfocitosis e hipoglucorraquia. Los títulos de fijación de complementos séricos y del LCR para histoplasma fueron positivos. La tomografía computada (TC) demostró que existía hidrocefalia y dos lesiones periventriculares con un marcado refuerzo con contraste. Se inició el tratamiento con altas dosis de ketoconazol y a continuación se administró fluconazol con una mejoría parcial del estado clínico y los valores de LCR. Finalmente se le practicó al paciente un tratamiento con anfotericina mostrando una completa remisión clínica, pero sin curación con valores variables en los controles de seguimiento a largo plazo de los títulos de complemento sérico y del LCR. En la actualidad, el paciente permanece asintomático y está tratado con itraconazol oral

Hidrocefalia crónica obstructiva por histoplasmosis meningo-cerebral / Chronic obstructive hydrocephalus due to meningeal and cerebral histoplasmosis

El presente caso describe un caso de histoplasmosis del sistema nervioso central con hidrocefalia obstructiva, que ha estado presente durante 8 años sin mayores secuelas o evidencias clínicas de infección activa en otros órganos, en un huésped inmunocompatible. La punción lumbar y el análisis del líquido cefalorraquídeo (LCR) revelaron un elevado nivel de proteínas, linfocitosis e hipoglucorraquia. Los títulos de fijación de complementos séricos y del LCR para histoplasma fueron positivos. La tomografía computada (TC) demostró que existía hidrocefalia y dos lesiones periventriculares con un marcado refuerzo con contraste. Se inició el tratamiento con altas dosis de ketoconazol y a continuación se administró fluconazol con una mejoría parcial del estado clínico y los valores de LCR. Finalmente se le practicó al paciente un tratamiento con anfotericina mostrando una completa remisión clínica, pero sin curación con valores variables en los controles de seguimiento a largo plazo de los títulos de complemento sérico y del LCR. En la actualidad, el paciente permanece asintomático y está tratado con itraconazol oral

[Schwannomatosis: report of a new case]. / Schwannomatosis: presentacion de un nuevo caso.

Schwannomatosis is a rare disorder, still not quite well defined, seldom described in the literature. In this paper we report the case of male. Patient, 52 years old, who in the last 30 years developed five subcutaneous tumors within his limbs peripheral nerves, which histologically proved to be schwannomas. A brain computed tomography showed a partially calcified tumor in the left temporal lobe which most likely was a meningioma. A thorough clinical examination was unable to find signs of type I or type II neurofibromatosis. The present condition, probably a form of phacomatosis, has to be distinguished from neurofibromatosis and is considered as an independent clinical entity whose origin still awaits further detailed investigations.

[Cerebral embolism of cardiac origin]. / Embolia cerebral de origen cardíaco.

We reviewed 538 charts of patients hospitalized with acute ischemic strokes between 1983 and 1991. The inclusion criteria for cardioembolism were: 1) sudden onset and maximal neurological focal deficit from the beginning, 2) brain CT showing an ischemic infarct, hemorrhagic infarct, or multiple infarcts, 3) cardioembolic sources demonstrated by echocardiography or heart catheterization, and 4) absence of stenotic-occlusive cerebrovascular disease. Sixty-nine patients (12.8%) filled the criteria for cardiogenic brain embolism. Cardiac sources were: 1) nonvalvular atrial fibrillation in 20 patients (29.0%), 2) rheumatic heart disease in 14 (20.3%), 3) nonischemic dilated cardiomyopathy in 13 (18.8%). Nine of these (69%) had cardiac involvement due to Chagas' disease, 4) ischemic heart disease in 11 (15.9%), and 5) other less common conditions such as bacterial endocarditis, mitral valve, and congenital heart malformation in 11 (15.9). Transient ischemic attacks preceding stroke occurred in 11 patients (15.9%), six patients had previous strokes, and 14 patients (20.3%) had silent infarcts. Early recurrence of embolism (three initial weeks) occurred in 5 patients (7.2%), and 28.6% of the patients had hemorrhagic transformation within this period. Taken together, our figures show that, although they are well in line with the current literature, nonischemic dilated cardiomyopathy is one of the main causes of cerebral embolism in our community. This reflects the presence of a regional factor, namely Chagas' disease.

Isquemias de territorio carotídeo en trombosis séptica del seno cavernoso / Brain ischemic lesions within the carotid artery territory en cavernous sinus thrombosis

Se presentan dos pacientes con clínica de tromboflebitis del seno cavernoso, quienes desarrollaron complicaciones isquémicas del territorio carotídeo asociado. Uno de ellos presentó embolia de la arteria central de la retina y trombosis carotídea proximal. El segundo mostró un infarto silviano homolateral al proceso infeccioso. El mecanismo iniciador de este inusual tipo de complicación podría ser la arteritis y estenosis focal del segmento intravenoso de la carótida interna, a partir del cual se desencadenarían fenómenos embólicos (distales al estrechamiento) y/o trombóticos (proximales al mismo)

Embolia cerebral de origen cardíaco. / [Cerebral embolism of cardiac origin]

We reviewed 538 charts of patients hospitalized with acute ischemic strokes between 1983 and 1991. The inclusion criteria for cardioembolism were: 1) sudden onset and maximal neurological focal deficit from the beginning, 2) brain CT showing an ischemic infarct, hemorrhagic infarct, or multiple infarcts, 3) cardioembolic sources demonstrated by echocardiography or heart catheterization, and 4) absence of stenotic-occlusive cerebrovascular disease. Sixty-nine patients (12.8

) filled the criteria for cardiogenic brain embolism. Cardiac sources were: 1) nonvalvular atrial fibrillation in 20 patients (29.0

), 2) rheumatic heart disease in 14 (20.3

), 3) nonischemic dilated cardiomyopathy in 13 (18.8

). Nine of these (69

) had cardiac involvement due to Chagas disease, 4) ischemic heart disease in 11 (15.9

), and 5) other less common conditions such as bacterial endocarditis, mitral valve, and congenital heart malformation in 11 (15.9). Transient ischemic attacks preceding stroke occurred in 11 patients (15.9

), six patients had previous strokes, and 14 patients (20.3

) had silent infarcts. Early recurrence of embolism (three initial weeks) occurred in 5 patients (7.2

), and 28.6

of the patients had hemorrhagic transformation within this period. Taken together, our figures show that, although they are well in line with the current literature, nonischemic dilated cardiomyopathy is one of the main causes of cerebral embolism in our community. This reflects the presence of a regional factor, namely Chagas disease.

Isquemias de territorio carotídeo en trombosis séptica del seno cavernoso / Brain ischemic lesions within the carotid artery territory en cavernous sinus thrombosis

Se presentan dos pacientes con clínica de tromboflebitis del seno cavernoso, quienes desarrollaron complicaciones isquémicas del territorio carotídeo asociado. Uno de ellos presentó embolia de la arteria central de la retina y trombosis carotídea proximal. El segundo mostró un infarto silviano homolateral al proceso infeccioso. El mecanismo iniciador de este inusual tipo de complicación podría ser la arteritis y estenosis focal del segmento intravenoso de la carótida interna, a partir del cual se desencadenarían fenómenos embólicos (distales al estrechamiento) y/o trombóticos (proximales al mismo)

Embolia cerebral de origen cardíaco. / [Cerebral embolism of cardiac origin]

We reviewed 538 charts of patients hospitalized with acute ischemic strokes between 1983 and 1991. The inclusion criteria for cardioembolism were: 1) sudden onset and maximal neurological focal deficit from the beginning, 2) brain CT showing an ischemic infarct, hemorrhagic infarct, or multiple infarcts, 3) cardioembolic sources demonstrated by echocardiography or heart catheterization, and 4) absence of stenotic-occlusive cerebrovascular disease. Sixty-nine patients (12.8

) filled the criteria for cardiogenic brain embolism. Cardiac sources were: 1) nonvalvular atrial fibrillation in 20 patients (29.0

), 2) rheumatic heart disease in 14 (20.3

), 3) nonischemic dilated cardiomyopathy in 13 (18.8

). Nine of these (69

) had cardiac involvement due to Chagas disease, 4) ischemic heart disease in 11 (15.9

), and 5) other less common conditions such as bacterial endocarditis, mitral valve, and congenital heart malformation in 11 (15.9). Transient ischemic attacks preceding stroke occurred in 11 patients (15.9

), six patients had previous strokes, and 14 patients (20.3

) had silent infarcts. Early recurrence of embolism (three initial weeks) occurred in 5 patients (7.2

), and 28.6

of the patients had hemorrhagic transformation within this period. Taken together, our figures show that, although they are well in line with the current literature, nonischemic dilated cardiomyopathy is one of the main causes of cerebral embolism in our community. This reflects the presence of a regional factor, namely Chagas disease.

Peripheral nervous system and spinal cord involvement in lymphoma.

Nine-hundred-eighty-nine patients with diagnosis of lymphoma were studied. Forty-six cases (4.6%) had compressions of the spinal cord or roots. Forty-two patients (4.2%) had Herpes zoster virus infections, which in 6 cases were of disseminated type. The major predisposing factors for infection were: advanced stage of lymphoma, previous systemic chemotherapy and splenectomy. Toxic polyneuropathy secondary to chemotherapy was found in 39 patients (3.9%). In 14 cases, the polyneuropathic symptoms were the main complaint (Group 1), while in the remaining 25 cases the diagnosis was made during neurological consultations because of unrelated symptoms (Group 2). Both groups did not have significant differences in the total dose of chemotherapy received. The electrophysiological studies showed an axonal neuropathy in both groups. The discontinuation of chemotherapy was found to be a limiting factor in the appearance of neuropathic symptoms. Other less frequent forms of involvement were: compression of peripheral nerves or nerve plexi from lymphadenopathies (3 cases), radiation myelopathy (1 case), and Guillain-Barré Syndrome associated with Hodgkin's Lymphoma (1 case).

Craniocerebral involvement in lymphoma.

Nine-hundred-eighty-nine patients with lymphoma were studied. Fifty-three cases (5.3%) had lymphomatous craniocerebral infiltration. The principal factors of risk for this complication were: advanced stage of the lymphoma (III or IV), diffuse histiocytic, diffuse poorly differentiated lymphocytic, or mixed cellularity lymphoma histological type, bone marrow involvement, and previous systemic chemotherapy. Thirty-two per cent of the cases of meningeal lymphomatous infiltration were asymptomatic and represented autopsy findings. CT-scan was an useful test to detect brain focal parenchymatous infiltration, as opposed to meningeal infiltration. Mean survival time in patients with lymphomatous meningeal infiltration was 4.3 months, following the combined use of systemic chemotherapy, radiation therapy and intrathecal methotrexate. Two cases had primary cerebral lymphoma, although without associated immunodeficiency. Twenty patients (2%) had intracranial hemorrhage, in clear relationship with platelet alterations. Fifteen patients (1.5%) had CNS infection, caused by common bacteria or opportunistic agents. In 7 cases, the diagnosis was made at autopsy. Thirty-six autopsies were performed. In 8 cases (22%), pathologic findings such as, demyelination, microcalcifications, coagulative necrosis, or gliosis, suggested complications from treatment.

Type 2 neurofibromatosis with Lisch nodules.

We describe a patient who, throughout a period of 6 years, had several cranial tumors in different locations. Bilateral acoustic neuromas, frontal meningiomas and a brain stem schwannoma were found on clinical and CT scan examinations and were histologically confirmed after surgery. These findings were associated with cutaneous neurofibromas and large café au lait spots suggesting the diagnosis of neurofibromatosis (NF) type 2. However, the presence of Lisch nodules, which characterizes NF-1, makes this patient rather unique. Clinical findings in the patient's relatives suggested the existence of NF-1 within the family. That is, the patient combines features of both types of NF.